In the information age of today, the use of images is becoming increasingly popular. In particular, images depicting the world surrounding us are frequently used for all kinds of purposes. The images may be available via Internet, such that people may have access to the images from a web browser on a computer or a mobile phone. For instance, images of places may be associated with a map such that it is possible for a user to look at a view of a point of interest on the map or that a user may be presented with views along a route for facilitating finding the way between two locations.
Also, images may easily be captured e.g. by means of pocket-size cameras or mobile phones that are provided with a camera function. In fact, many people carry a camera in their mobile phone all the time and are able to take a photo whenever it is desired. Hence, a database of images of the world surrounding us may quickly be provided with a large number of images if any user in the world is allowed to contribute images to the database.
An application that enables a user to navigate, i.e. to switch the image that is being viewed in order to experience moving through a scene, through a set of images in a database may be optimized for providing the best possible experience to the user navigating through the images. Typically, the database is provided with the images that are desired for providing a good experience to the user and relationships between the images are defined in order to correlate the images to each other such that navigation through the images is provided in a desired manner. The correlation of the images to each other may be adapted to the specific application in order to optimize the experience provided to the user as the user navigates through the images.
An example of an application providing navigation through images that may be captured by users of an application is described in Arpa, A. et al, “CrowdCam: Instantaneous Navigation of Crowd Images Using Angled Graph”, 2013 International Conference on 3D Vision—3DV 2013, pages 422-429. The application provides a possibility for users to capture photos of an event and to share the photos to take advantage of each others' perspectives such that navigation through views of the event from different perspectives is possible. The photos are represented as vertices of a weighted graph, where edge weights describe similarity between pairs of images. Angles of the graph are defined as a pair of edges with a common vertex. The weighted graph may be augmented with a set of angles forming a weighted angle graph including angle weights, which penalize turning along the corresponding angle. The weighted angled graph is formed so as to promote straight paths through the graph. Hence, the weighted angled graph is also constructed so as to adapt the weights to the desired experience when a user navigates through the graph.
In order to enable a user to navigate through images using an application for a specific purpose, the provider of the application needs to collect the set of images through which navigation is to be enabled. This implies that several providers may need to collect images of the same scene in order to each be able to provide their application to users. It would therefore be desirable to enable use of one database of images for several types of applications such that the respective providers of applications need not collect their own set of images.